"It is only by demanding the impossible of the piano that you can obtain from it all that is possible. For the psychologist this means that imagination and desire are ahead of the possible reality. A deaf Beethoven created for the piano sounds never heard before and thus predetermined the development of the piano for several decades to come. The composer's creative spirit imposes on the piano rules to which it gradually conforms. That is the history of the instrument's development. I don't know of any case where the reverse occurred."